Influence of Exposure Temperature on Chloride Diffusion into RC Pipe Piles Exposed to Atmospheric Corrosion

Abstract

This paper focuses on the influence of exposure temperature (21, 30 and 50°C) on chloride diffusion into reinforced concrete (RC) pipe pile exposed to atmospheric corrosion. The governing equation of chloride diffusion into RC pipe pile is described and solved analytically by using the Bessel functions. The salt spray tests are set up to simulate the environment of atmospheric corrosion. RC pipe piles with three different water-to-cement (w/c) ratios (0.30, 0.45, and 0.55) are exposed to 5% chloride salt spray for 32 days at the three levels of exposure temperatures. The chloride concentration profiles, surface chloride concentration, apparent and effective diffusion coefficients, activation energy, and binding capacity values of RC pipe piles with different w/c ratios at different exposure temperatures are presented. The results of the present study indicate that an increase in exposure temperature results in higher free chloride concentration. The surface chloride concentration and apparent and effective diffusion coefficients increase with the increase in temperature for a certain relative humidity. The binding capacity increases significantly with the increase of exposure temperature from 21 to 30°C; however, the binding capacity decreases slightly with the increase of exposure temperature from 30 to 50°C. The log-variation of apparent diffusion coefficient with the inverse of absolute temperature is linearly distributed. Therefore, it could be concluded that the chloride diffusion into RC pipe pile follows the Arrhenius theory.